Transcript College Physics Chapter 1 Introduction Science is a Philosophy     It is not science without data It is not science without measurement errors (somehow) It is not.

College Physics
Chapter 1
Introduction
Science is a Philosophy
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It is not science without data
It is not science without
measurement errors (somehow)
It is not science unless it can be
reproduced (objectivity)
Math is like the grammar of
science
Fundamental Quantities
and Their Dimension
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Length [L]
Mass [M]
Time [T]
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other physical quantities can be
constructed from these three
Systems of Measurement
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Standardized systems
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SI -- Systéme International
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agreed upon by some authority
1960 by international committee
main system used in this text
also called “mks” units
cgs – Gaussian system
US Customary
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nits of common usage
Prefixes
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Metric prefixes correspond to
powers of 10
Each prefix has a specific name
Each prefix has a specific
abbreviation
See table 1.4
Structure of Matter
Dimensional Analysis
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Technique to check the correctness
of an equation
Dimensions (length, mass, time,
combinations) can be treated as
algebraic quantities
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add, subtract, multiply, divide
Both sides of equation must have
the same dimensions
Uncertainty in
Measurements
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There is uncertainty in every
measurement, and uncertainty
carries over through calculations
Lab uses rules for significant
figures to approximate the
uncertainty in calculations
Conversions
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Units must be consistent (time=time)
Units carry value! (1 m = 100 cm)
You can manipulate words in equations
just like you manipulate numbers
Example:
Cartesian coordinate
system
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Also called
rectangular
coordinate
system
x- and y- axes
Points are labeled
(x,y)
Plane polar coordinate
system
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Origin and reference
line are noted
Points labeled (r,q)
Point is distance r
from the origin in
the direction of angle
q, (counterclockwise
from reference line)
Trigonometry Review
More Trig
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Pythagorean Theorem
To find an angle, you need the inverse
trig function
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for example,
Be sure your calculator is set
appropriately for degrees or
radians
Must beware of quadrant ambiguities
Polar Coordinates Example
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Convert the
Cartesian
coordinates for
(x,y) to Polar
coordinates
(r,q)
How High Is the Building?
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Determine the height of the building
and the distance traveled by the
light beam
Problem Solving Strategy